orgo ch8

elimination reaction

alcohol or alkyl halide undergo elimination reaction by loss of group from one carbon and h from adjacent carbon to form alkenes

organohalides form what

elimination reaction form alkynes

elimination of alcohols by e1

solvents are h2so4 or h2po4, a reversible reaction, secondary and tertiary favor carbocation

regioselectivity

the formation of more stable product predominates as major product

which are more stable alkenes

highly substituted alkenes are stable product

stability of alkenes

alkenes with more carbon more stable, trans more stable than cis

cyclic alkene stability

endocyclic more stable than exocyclic

unimolecular reaction of alkyl halide- Cl, Br, I

first carbocation forms, then solvent act as base

e2 reaction is stereospecific

reactions where stereochem of product depends on the stereochem of starting material

e2 is stereoselective

reaction where one stereoisomer is formed in preference to another

e2 reaction characteristics

the e pair of ch bond interact with sigma orbital and h is removed, need heat, lg and beta h must be anti

e2 is regioselective

the more stable alkene is more substituted

factors affecting e2

weak base is good lg, more substituted alkene is major product, protic solvents are used in e2

e2 reaction of alcohols

primary alcohol converted to alkylsulfonate a good lg, then undergo e2 reaction